Incandescent-arc device



May 192s.

G. KLA

INCANDESCENT ARC DEVICE Filed July 28 1924 lnv Patented May 12, 1925aSTATES v anna PATENT o FIc-E.

GljN'IHER KLAHRE, 0F BERLIN, GERMANY, ASSIGNOR TO GENERAL ELECTRIC COM-PANY, A CORPORATION OF NEW YORK.

INCANDESCENT-ARG DEVICE.

Application filed July 28, 1924. Serial No. 728,530.

T 0 all whom it may concern:

Be it known that I, GiiNTHEn KLAHRE', a citizen of Germany, residing atBerlin, Germany, have invented certainnew and useful Improvements inIncandescent-Arc Devices, of which the following is a specification.

The present invention relates to devices in which an arc-like dischargeis operated in an inert gas between refractory electrodes and isparticularly concerned with the starting of the discharge between saidelectrodes by contact and separation of electrode members.

Indevices of this type which are provided with contact startingmechanism, a separation of the electrodes usually is effected by athermostatic member, which. when heated, draws the electrodes apart.with the resulting formation of an are. To insure positive contactbetween the electrodes, when the arc is not operating and to prevent theanode from being drawn away from the cathode prematurely. the anodeheretofore has been arranged to press against the cathode when thedevice was not operating. As a result of this condition the electrodestended to remain in contact for several seconds, while current passedthrough them. Because of the high current density at the points ofcontact it often happened that the anode became welded or frozento thecathode before the thermostatic starting device could cxert sufiicientforce to separate the electrodes. As a result the thermostatic devicesometimes was unable to separate the electrodes and in that eventthedeviee was rendered inoperative.

According to the present invention a construction is provided whereby apositive starting of an arc lamp, or other device, is attained withoutany danger of welding of the electrodes. This result is obtained byproviding a resiliently supported stop or motion-limiting device.against which the movable electrodes will bear. and from which it willbe separated. preferably with l a rubbing contact when the arc isstarted.

This stop device is conductively connected with the opposite electrode,preferably the cathode, so that when the movable electrode, in thepreferred case the anode, is

. separated from the stop device, an arc will be started which willlater be transferred to the 'electrode to which the stop device isconnected.

when the arc is operating, and Figs. 3, 4, y

5 and 6 illustrate modifications of my in vention.

The lamp shown in Fig. 1 comprises a glass bulb a containing an inertgas, such as argon, neon, nitrogen and provided as usual with ascrew'base j, to which the leads 0 and d are conductively connected. Theelectrodes and starting mechanism are carried by a glass stem 6 intowhich the leads 0 and d are sealed in the usual man nor. The bar-shapedcathode e, which preterably consists of tungsten, and which may beprovided with a coating of thorium or other oxide, is supported uporrthestem 3) by wires f and g. The anode it has been shown as of sphericalshape, although of course it may assume other forms. The anode whichpreferably also consists of tungsten is carried by a support 2', whichis mounted upon the stem b of the lamp 'through the intermediary of athermostatic held by the radial supports w arranged around the stem ofthe lamp and is connected to the terminals of the lamp in series withthe electrodes, the circuit being from the leading-in conductor (2through the resistor wire n, a support 0, the anode stem 2', the stopplate m, the cathode support f to the opposite leading-in conductor 0.One portion of the resistor n is arranged as indicated by 0approximately parallel to the bi-metal stripk, so that when the lamp is,switched on the thermostatic strip is is not only heated by currentpassing therethrough, but also by heat radiated from the resistor 0 andhence is caused to separate the anode h from the stop plate Z. Thisseparation occurs by a curved motion about the support of the anode inthe direction of the I strikes the end of the cathode as shown in Duringthe brief period of simultaneous motion of the anode and the stop plate,the anode slides somewhat upwards on the surface of the stop plate andtherefore the anode does not remain long enough in contact at oneparticular point. to permit welding. The distance between the stop plateand the cathode is so adjusted that the arc is formed by the separationof the anode andthe stop plate at the int-taut of contact ot the stopplate with the cathode. Hence, the arc immediately jumps over to thecathode. The anode may continue to move in the direction indicated bythe arrow through the action of the thermostatic support until itremains in the position shown in Fig. 2. being separated from thecathode by a distance suitable for the operation of thc arc. The stop Zprclcrably consists of a polishci'l tungsten plate to facilitate thesliding of the are upon its surface in order to prevent displacement oithe anode and the stop plate especially during transportation of thelamp. loop-shaped guide) surrounding the anode support '11 is mountedupon the s :m b.

Various modifications in the construction of the stop plate Z can beused. As shown in Fig. 3 thelimit sto may consist of a semisphericalbody Z, which is threaded directly upon the bar-shaped cathode c. a spral spring g. surrounding the cathode. being provided to hold the stopagainst the anode A. A forward travel of the stop Z is limited by acheck 1'. but it is possible to omit the check r in the case the s n'ingtension is correctly chosen. The different positions of the stop I andthe anode ll during starting are indicated by dotted lines in Fig. 3.

Although the cathodihas'bccn shown for illustrative purpo e in Figs. 1and 3 as consisting of a bar. it may assume various other shapes. inFigs. 4- and 5 a block-shaped cathode s has been illustrated. In thiscase also the resilicnt supported stop plate Z may assume a. restingposition againstthc cathode 5 during the operation oi the arc. althoughof course the forward travel of the stop plate may be limited b check asalready shown in Fig. 3. I

In Fig. 6 a. construction has been shown in which the resiliency (if thestop 1 is secured by making the snp 'iorlsf, g of the cathode yieldingAs shown in Fig. 6 fiat springs t are inserted in the. cathode supports.the stop plate being in this case an integral part of thr cathodestructure. 'When the anode It is; drawn in the direction of the arrow bythe action of the thermostatio support, the cathode structure firstfollows the motion of the anode. The anode slides over the stop plate Zand fi'iially is separated therefrom, the are springing over 2. An arcdevice comprising the combina- I tion of a cathode adapted to beoperated at incandescence, a cooperating anode, a yielding conductivestop member connected to one of said electrodes .and engaging when saiddevice is notoperating with the cooperating electrode, and means for,drawing said cooperating electrode away from said memher. to strike anarc whcn the device is to be started. r

3. An arc device comprising the combination of an incandescible cathode.a cooperating anode. a yielding conductive member connected to saidcathode, and engaging when said device is not operating. with saidanode, a thermostatic support for said anode. and means for generatingheat when said device is to be started to cause said anode to leave saidstop member.

4. An arc device comprising the combination of a tungsten cathode, acooperating anode, a stop mcn'iber. consisting of a smooth plate ofrefractory metal and a springy support. applied in said devicev to causesaid plate to bear against said anode when the device is not operating.tcmpcraturc-responsire means for separating said anode and stop memberand a resistor arranged to thermally actuate said separating means.

An incandescent arc lamp comprising the combination of a tungstencathode (5-). a coopcrating' anode (It), a bi-inetal support (7:) forsaid anode, a mechanical limit stop bearing against said anode whichcomprises a smooth plate (Z) and a'resilient holder (m), a support (f)positioned to hold said stop against said cathode when the lamp isoperating. means for heating said iii-metal support to cause the anodeto leave said stop and to strike an arc. an enclosingenvelope (1:) andan inert gas hllinp therein.

0. An ciectric lamp comprising a scaled bulb. a gaseous iillinptherefor. cooperating electrodes of refractory metal. a yieldingconductive stop member connected to the cathode. spaced away therefromand located to engage with the anode when the device is not operatingand means for separating said anode from the stop member with a rubbingmotion when the lamp is to be lighted.

In witness whereof, I, have hereunto set my hand this 7th day of July,1924.

' GUNTHER KLAHRE.

